add aloha/2025hcpc

storage/aloha/cpp/2025hcpc-div1-C.cpp

@@ -0,0 +1,39 @@
+#define MAX_N 200'000
+#include <iostream>
+
+using namespace std;
+using ll = long long;
+
+ll ans;
+int N, M;
+ll sum[MAX_N+1][26];
+string S, T;
+
+void init();
+void solve();
+
+int main() {
+    ios_base::sync_with_stdio(0);
+    cin.tie(0); cout.tie(0);
+
+    init();
+    solve();
+    cout << ans << "\n";
+}
+
+void init() {
+    cin >> N >> M;
+    cin >> S >> T;
+}
+void solve() {
+    for (int i = 0; i < S.size(); i++) {
+        char c = S[i];
+        for (int j = 0; j < 26; j++) sum[i+1][j] = sum[i][j];
+        sum[i+1][c-'a']++;
+    }
+
+    for (int i = 0; i < T.size(); i++) {
+        char c = T[i];
+        ans += sum[S.size()-T.size()+i + 1][c-'a'] - sum[i][c-'a'];
+    }
+}